In the field of time indicating clocks, a conventional clock operates in such a manner that the acoustic data of, for example, a Westminster chime is read out of an acoustic data output device every 15 minutes to generate a melody. In such a clock, in order to decrease the storage requirements of a storage circuit for acoustic data, the fundamental waveform of one sound of a bell is stored in a ROM in the form of PCM data, for example, whereby a melody can be performed on the basis of the data of-only one sound because the musical scale can be changed by changing the frequency of a clock signal used in reading out the data.
The foregoing conventional clock outputs a melody by repeatedly reading out one data and thus cannot generate a plurality of sounds concurrently in an overlapped mode. Specifically, since a series of sounds is generated one sound after another, it cannot be heard as a series of contiguous sounds, giving only a flat melody or rough music.